Blasting method and apparatus



' June 15, 1937;

R. W. DULL APPARATUS Filed June 17, 1935 BLASTING METHOD AND 1720672232" Rcgyrrzazzd' Zffizazz Patented June 15, 1937 PATENT OFFICE BLASTING DIETHOD AND APPARATUS Raymond W.

Safety Mining Company,

Illinois Dull, La Grange, Ill., assignor to a corporation of Application June 17, 1933, Serial No. 676,227

20 Claims.

This invention relates to a new method of applying energy in the breaking down of coal or in the performance of any analogous class of work and to a type of apparatus designed to carry out the new method.

In a pending application filed in my name under date of May 27th, 1933 Serial Number 673,146 there is disclosed a method of breaking down coal by means of controlled pressures and in particular an apparatus consisting of a substantially indestructible cartridge adapted to be positioned in a drill hole in the coal to be broken and to receive a charge of high pressure air while so positioned in the drill hole, said cartridge also having therein a differential valve designed to effect the release of the charge of high pressure air vthrough a suitable discharge arrangement provided on one end of the cartridge. According to this pending application the charge of high pressure air is introduced into the cartridge by means of a suitable pipe or high pressure hose extending from the cartridge to a remote point where it has connection with a suitable source of high pressure air which may be in the form of an air receiver or a compressor, and the discharge of the cartridge is efiected by means of a valve positioned in the pipe or hose line, said valve being designed to stop the flow of high pressure air from the source and to vent to the atmosphere the section of pipe or tubing extending from the valve to the cartridge. The sudden drop in pressure caused by venting the pipe and of a portion of the cartridge in communication therewith serves to bring about the operation of the difierential valve, thus permitting the entire charge of high pressure air to escape from the cartridge in an instantaneous manner.

While the discharging-action of the cartridge covered in the pending application as disclosed above is quite satisfactory and corresponds with the standard practice of subjecting the coal to a single discharge of a considerable volume of energy; experimentation has developed that certain important advantages may be obtained by dividing the normal volume of discharged energy into a rapid succession of distinct discharges. It has been found possible to accomplish this desirable result by a simple modification of the cartridge described in the aforementioned application, which modification together with the newly developed method constitute the principal subject matter of the present application.

The primary object of the invention is to provide a method whereby the application of any given quantity of energy may be applied to the work to be accomplished in a succession of distinct releases, and with the provision of an apparatus suitable for the practice of this method.

Referring to the drawing Figure 1 is a view in longitudinal section illustrating a typical form of apparatus according to the present invention. Figure 2 is a view in longitudinal section illustrating a slight modification of both the method and apparatus represented in'Figure 1.

Referring to Figure 1, there is shown a cartridge body I having a terminal cap 2 and a discharge cap 3. The body is formed with an internal chamber 5 designed to receive and hold a substantial quantity of high pressure air or other gas. The cartridge is provided with a differential valve mechanism consisting of a rod extending throughout the length of the cartridge and having secured on one end thereof a valve designed to close the opening of the discharge cap 3 and on its opposite end is provided with a plunger slidably fitting the bore of chamber I formed in the terminal cap 2. The plunger is provided with a plurality of ports which extend entirely therethrough and adjacent the plunger there is provided a spring compressed check valve which serves to limit the flow of air or gas to a single direction.

High pressure air may be introduced into the cartridge through a charging passage 6 formed in terminal cap 2, a nipple I having threaded connection with the terminal cap, a piping 8 extending therefrom to a' suitable source of high pressure air indicated generally at 9. This source of high pressure air may take the form of a compressor or of a high pressure air receiver, as desired. Provided in the pipe line 8 there is a valve I having a lateral discharge port l0. Attention is directed to the fact that at this point the charging passage 6 is of relatively small cross sectional area.

In the practice of this method and the operation of the typical apparatus illustrated, the cartridge is first inserted in a drill hole formed in the material to be broken and is then connected by suitable piping or tubing 8 to a source of high pressure air 9. This source of high pressure air is preferably located at a point suflicient- 1y remote from the cartridge to provide adequate safety. The movement of valve I!) to one position permits the flow of high pressure air from the source 9 directly into chamber 4 of the cartridge from whence it flows through the several ports formed in the plimger past the check valve into moving valve I0 into position to cut 011 the flow of high pressure air from the source 9 to the cartridge and to vent to the atmosphere the section' of pipe or tubing 8 extending between valve l0 and the cartridge a substantial drop in pressure is brought about in chamber 4 which, owing to the substantially higher pressure in chamber 5 results in an instantaneous movement of the entire diiferential valve mechanism toward the terminal end of the cartridge, thus permitting the flow of high pressure air from chamber 5 outwardly through the discharge cap 3. Bearing in mind the above comment regarding the relatively small cross sectional area of the discharge passage 6, it will be readily understood that the escape of high pressure air from chamber 5 through the discharge cap 3 for only a very small fraction of a second will result in a drop in pressure within chamber 5 to a point below the value of the pressure in chamber 4. When this condition arises the difierential valve mechanism will immediatelymove axially in the opposite direction and close the discharge opening of cap 8. At this point it is well to refer again to the relatively small area of passage 6 and to mention the fact that if this passage were of sufilciently large cross sectional area the closing action of the difierential valve as just described would not occur. In other words, if the area of passage 6 were such that the venting of pipe 8 would result in a more rapid reduction in pressure within chamber 4 than occurs in chamber 5 when the difierential valve is in open position, the dif-- ferential valve mechanism would remain in open position until the entire charge contained in chamber 5 had escaped through the discharge cap 3. It should be pointed out also that the rate of drop in pressure within chamber 4 prior to the initial opening of the differential valve is not important as the venting of chamber 4 to the atmosphere through any opening however small would eventually result in a differential pressure condition wherein the pressure in chamber 5 would exceed that in chamber 4 by a suificient margin to cause the opening of the difierential valve. Once the difierential valve has been moved to open position, however, the relative rate of pressure drop in chambers 4 and 5 becomes important and it is for this reason that the small area of the passage 6 results in the action above described.

It should be understood, of course, that the opening and closing of the diiferential valve as described above represents but a single cycle of the operation-and that in practice this valve will open and close a number of times, providing a succession of distinct discharges, depending as to number and intensity upon the pressure and volume of air or other gas introduced into the :artridge. Experience indicates that with a :harge of air at 10,000 pounds pressure in chamoer 5 of the cartridge the result will usually be four or five distinct discharges diminishing in :orce and volume progressively from the first to ;he last. Although the action has been referred ",0 as a succession of distinct discharges it should e understood that these discharges occur in ex- :eedingly rapid succession. The repeating action of the diiferential valve continues in any case until the pressure values within the cartridge have dropped to a point where they are no longer suflicient to actuate the differential valve.

The method and apparatus described above are designed particularly for underground operation where a source of high pressure air is available. The difi'erential valve type cartridge however is well adapted for charging at some central point either within or without the mine from which it may be transported to-any desired point oi use.

In adapting the cartridge to this class of service it is necessary to confine the charge until such time as it is desired to use the same and to then effect the release thereof after the cartridge has been positioned in or adjacent the work to be accomplished. Referring to Figure 2 there is shown a cartridge designed for this class of service. This cartridge is essentially the same as that illustrated in Figure 1 except that in place of passage 6 of Figure 1 there is provided a passage IT in Figure 2 which communicates with chamber 4 of the terminal cap and with an enlarged passage l6 also formed in the terminal cap. This passage 5 is normally closed by a disc l5 which may be made of metal, fiber or other suitable material possessing suflicient strength to withstand the pressure involved. The disc I5 is held in sealing position by means of a hollow nut M. A valve I3 is provided in the terminal cap in this case to permit the introduction of high pressure air into the cartridge at the central charging station mentioned above.

In order to effect the discharge of a cartridge of the type illustrated at Figure 2 it is simply necessary to puncture or shear out the center of disc l5 thereby venting chamber 4 to the atmosphere. This may be accomplished by means of an air gun as indicated generally at H which is designed for attachment to the end of the cartridge. This gun may consist of a pneumatically actuated plunger carrying a small chisel designed to be forcefully projected against the disc l5, to shear out the central portion thereof. The flow of air outwardly from chamber 4 through passage l1, I6 and through the ruptured disc l5 enters the end of the air gun II and escapes through a plurality of radial ports II. This, of course, results in a drop in pressure in chamber 4 and consequently in an immediate opening of the differential valve. If the passage I! were of the same diameter as passage l6 it is probable that the puncturing of disc i5 would result in a single discharge of the entire volume of high pressure air contained in chamber 5, but owing to the restriction of port I! the repeating action described above is accomplished.

In view of the foregoing it should be realized that the present invention provides a new and improved method of applying energy to the breaking down of coal or to analagous work which method is characterized by the division of a total force or charge of potential energy into 'a number of distinct discharges in rapid succession. The eiiectiveness of successive energy impulses, which might be likened to a series of hammer blows, in the performance of useful work will be readily appreciated. The invention also provides a simple and reliable mechanism for the practice of this desirable method of operation. It should be pointed out also that this desirable method of operation combines within it the ability to effect the discharge of the cartridge at, accurately controlled pressures within the entire range of the pressure capacity of the source of supply. In other words, referring particularly to Figure 1, it is possible to effect the discharge of the cartridge by simply operating the valve' "I when the pressure within chamber 5 has reached any desired value and in addition the release of the charge whatever its value may be will occur in a succession of distinct discharges.

I claim:

1. A method of breaking down materials which consists in confining a single energy storing charge of expansible fluid at material breaking pressure in the material to be broken down, and

' releasing said charge in the material to be broken in a succession of distinct discharges to break down the material by the expansive action of the fluid thereon.

2. A method of breaking down materials which consists in confining a predetermined quantity of expansible material possessing potential energy at material breaking pressure in the material to be broken and applying said quantity of material possessing potential energy to the material to be broken in a succession of distinct energy impulses to break down the material by the expansive action of the expansible material thereon.

3. A method of breaking down coal or other materials which consists in confining a quantity of material possessing potential energy in or adjacent the .material to be broken down, and applying said potential energy to the work in a rapid succession of distinct energy impulses of, progressively diminishing intensity.

4. A method of breaking down materials which consists in the introducing and confining a controlled quantity of expansible material possessing potential energy .at material breaking pressurevin' the material to be broken down, and applying said quantity of material possessing potential energy to the material to be broken in a succession of distinct energy impulses to break down the material by the expansive action of the expansible material thereon.

5. A method of breaking down coal or other materials which consists in introducing and confining a controlled quantity of material possessing potential energy in the material to be broken down, and applying said potential energy to the work in a rapid succession of distinct energy impulses of progressively diminishing intensity.

6. An apparatus of the character described comprising a cartridge adapted to receive la charge of high pressure air or other gas and embodying a discharge orifice for the release of such charge, a differential valve for controllingsaid discharge orifice, and means for causing said valve to' alternately open and close, thereby releasing said charge in a succession of distinct energy impulses.

"l. A material breaking apparatus comprising container means for confining gas compressed to a desired work performing pressure; valve means for controlling the discharge of said gas,

and pressure responsive means for operating said toa desired work performing pressure, valve means for controlling the discharge of said gas, and pressure responsive means acted upon by the compressed gas confined in said first mentioned means for operating said valve means 9. In a blasting cartridge, a container for receiving a blasting charge of expansible fluid and adapted for insertion in a blast hole drilled in the material to be broken, and means operative subsequent to the positioning of the cartridge in the blast hole for releasing said charge from said container into the material to be broken in a rapid succession of distinct energy impulses to break down the material by the expansive action of the fluid thereon.

10. In a blasting cartridge, means insertable in the material to be broken for receiving and confining a quantity of blasting pressure and having a discharge orifice, and valve means for releasing the blasting pressure from said receiving means through said discharge orifice into the material to be broken in a plurality of distinct blasts in rapid succession.

11. In a blasting cartridge, a container for receiving a blasting charge at material breaking pressure and insertable in an opening in the material to be broken, a valve for controlling the discharge of said charge from said container, and means for effecting alternate opening and closing of said valve to discharge said charge from said container into the material to be broken in a number of distinct energy impulses.

12. In a blasting cartridge, means insertable in the material to be broken for receiving a quantity of expansible fluid at blasting pressure, and means for releasing the fluid from said receiving means into the material to be broken in a plurality of distinct blasts to break down the material by the action of the fluid thereon.

13. In a blasting cartridge, means insertable in the material to be broken for receiving a quantity of expansible fluid at blasting pressure, and means for releasing the fluid from said receiving means into the material to be broken in a plurality of distinct blasts in rapid succession to break down the material by the action of the fluid thereon.

Q 14. A material'breaking apparatus comprising container means to be charged with highly compressed gas at material breaking pressure and means operatively associated with the aforementioned means for releasing said gas in the material to be broken in a succession of distinct energy impulses to break down the material by the action of the gas thereon.

15. A material breaking apparatus comprising container means for confining gas compressed o a desired work performing pressure in the material to be broken, and pressure responsive means for releasing said gas in the material to be broken in a succession of distinct energy impulses to break down the material .by the action of the gas thereon.

16. A material breaking apparatus comprising container means for confining gas compressed to a desired work performing pressure in the material to be broken, and pressure operated valve means for releasing said gas in the material to be broken in a succession of distinct energy impulses to break down the material by the action of the gas thereon.

17. In a material breaking apparatus, means for confining gas compressed to a desired work performing pressure and differential valve means located within the aforementioned means constructed and arranged to effect release of said gas into the material to be broken in a succession of distinct energy impulses to break down the material by the action or the gas thereon.

18. A blasting apparatus comprising a cartridge structure insertable in the material to be broken and adapted to confine a predetermined volume J of gas compressed to a pressure sufliciently high to accomplish the desired work, means for charging the cartridge, and means for intermittently releasing fractional portions of the charge from said cartridge in the material to be broken.

19. A blasting apparatus comprising acartrid ge I structure insertable in the material to be broken and adapted to confine a predetermined volume of gas compressed to a pressure sufiiciently high aoaaese 

